Apparatus and method for assembling a permanent magnet motor rotor

ABSTRACT

An apparatus for assembling a permanent magnet motor rotor includes a first-end positioning assembly, a plurality of connectors, and a second-end positioning assembly. The first-end positioning assembly is utilized to fix a first-end rotor core. The second-end positioning assembly is utilized to fix a second-end rotor core. The connectors are utilized to connect and fix the first-end positioning assembly with the second-end positioning assembly. Each first longitudinal axis of each first positioning element of the first end positioning assembly is different from each second longitudinal axis of each second positioning element of the second end positioning assembly. In addition, a method for assembling a permanent magnet motor rotor is also provided.

This application claims the benefit of Taiwan Patent Application SerialNo. 108123296, filed Jul. 2, 2019, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION (1) Field of the Invention

The invention relates to an assembling apparatus and a method thereof,and more particularly to an apparatus for assembling a permanent magnetmotor rotor and a method thereof.

(2) Description of the Prior Art

In order to reduce cogging torque of a permanent magnet motor, a rotorcore is usually formed in sections, and neighboring sections of therotor core are differed in an angle with respective to a common centralaxis, such that the cogging torques of adjacent sections of the rotorcore would be close but canceled to each other. Thereupon, the entirecogging torque would be substantially reduced.

Refer to FIG. 1 through FIG. 3; where FIG. 1 is a schematic view of arotation shaft and a key plate in the art, FIG. 2 demonstratesschematically the rotation shaft of FIG. 1 mounted with a first rotorcore in the art, and FIG. 3 demonstrates schematically the rotationshaft of FIG. 1 mounted with a sectional skewed rotor assembly in theart. As shown, the sectional skewed rotor assembly PA1 includes arotation shaft PA11, a plurality of key plates PA12 (only one labeled inthe figure) and a plurality of rotor cores PA13 a, PA13 b, PA13 c.

The rotation shaft PA11 is furnished with a plurality of key ways PA111(only one labeled in the figure), and each of the key ways PA111 isarranged at an individual angle. The key plates PA12 are mounted intothe corresponding key ways PA111. In each of the rotor cores PA13 a,PA13 b, PA13 c, a plurality of rotor grooves PA131 a, PA131 b, PA131 care furnished to corresponding peripheral surfaces thereof,respectively, and a plurality of buckling slots (not shown in thefigure) are furnished to corresponding inner surfaces thereof at placesrespective to the key plates PA12, in which the buckling slot is usedfor buckle the corresponding key plate PA12.

In a typical manufacturing process, the first key plate PA12 is fittedinto the corresponding first key way PA111, and the rotation shaft PA11is plugged into the rotor core PA13 a. Then, the second key plate PA12is fitted into the second key way PA111, and then the rotation shaftPA11 is plugged into the rotor core PA13 b. Finally, the third key platePA12 is fitted into the third key way PA111, and then the rotation shaftPA11 is plugged into the rotor core PA13 c. Since these three key waysPA111 do not lie along the same vertical line, thus the rotor groovesPA131 a, PA131 b, PA131 c would not lie along another vertical line, butform individual angles to each other. Thereupon, the sectional skewedrotor assembly PA1 is formed.

However, the aforesaid manufacturing process using the key plates PA12and the key ways PA111 is tedious, time-consuming and costly for theinclusion of the key ways PA111 and the buckling slots. With theinvolvement of the key plates PA12 and the key ways PA111, the resultedrotor cores PA13 a, PA13 b, PA13 c would be hard to be dissembled, andthus difficult to be maintained. In the case that the sectional skewedrotor assembly PA1 occurs a damage, a replacement for the whole set ofthe sectional skewed rotor assembly PA1 would be inevitable. Namely, anymaintenance upon the rotor cores PA13 a, PA13 b, PA13 c by separatingthe key plates PA12 from the corresponding key ways PA111 would beunfeasible. In addition, the construction of the buckling slots wouldunbalance the corresponding rotor cores PA13 a, PA13 b, PA13 c.

SUMMARY OF THE INVENTION

In view that the conventional manufacturing process having the keyplates and the paired key ways is tedious, time-consuming and costly,further that the assembled product is hard to be disassembled,investigated and maintained, and more further that the construction ofthe buckling slots would cause to the corresponding rotor cores to beunbalanced, accordingly it is an object of the present invention toprovide an apparatus for assembling a permanent magnet motor rotor, suchthat at least one o f the aforesaid shortcomings can be resulted.

In this invention, an apparatus for assembling a permanent magnet motorrotor, used for a rotation shaft to penetrate through and thus beassembled with a first-end rotor core and a second-end rotor core in anassembly direction, includes a first-end positioning assembly, aplurality of connectors and a second-end positioning assembly.

The first-end positioning assembly has at least one first positioningelement, is furnished with a first through hole for the rotation shaftto penetrate therethrough, and is used for detachably connecting thefirst-end rotor core. The at least one first positioning element is usedfor plugging at least one of a plurality of first-rotor through holes ofthe first-end rotor core so as to fix the first-end rotor core. Theplurality of connectors are connected with the first-end positioningassembly. The second-end positioning assembly has at least one secondpositioning element, furnished with a second through hole positioned incorrespondence to the first through hole, and is used for detachablyconnecting the second-end rotor core and the plurality of connectors.The at least one second positioning element is used for plugging atleast one of a plurality of second-rotor through holes of the second-endrotor core so as to fix the second-end rotor core.

In addition, a first longitudinal axis for each of the at least onefirst positioning element to extend individually in the assemblydirection and a second longitudinal axis for each of the at least onesecond positioning element to extend individually in the assemblydirection are arranged in an offset manner.

In one embodiment of the present invention, the at least one firstpositioning element includes two said first positioning elements.

In one embodiment of the present invention, the two first positioningelements are symmetrical to the first through hole and connected to forma first reference line.

In one embodiment of the present invention, the at least one secondpositioning element includes two said second positioning elements.

In one embodiment of the present invention, the two second positioningelements are symmetrical to the second through hole and connected toform a second reference line, and an angle is formed while the firstreference line and the second reference line are projected in theassembly direction.

In one embodiment of the present invention, the apparatus for assemblinga permanent magnet motor rotor further includes at least one middlepositioning assembly. Each of the at least one middle positioningassembly has at least one middle positioning element, is furnished witha middle through hole positioned in correspondence to the first throughhole and the second through hole, and detachably connects a middle rotorcore and the plurality of connectors. The at least one middlepositioning element is used for plugging at least one of a plurality ofmiddle-rotor through holes of the middle rotor core so as to fix themiddle rotor core.

In one embodiment of the present invention, the at least one middlepositioning element of the at least one middle positioning assemblyincludes two said middle positioning element.

In one embodiment of the present invention, the two middle positioningelements are symmetrical to the middle through hole.

In another aspect of the present invention, a method for assembling apermanent magnet motor rotor, performed by utilizing the aforesaidapparatus for assembling a permanent magnet motor rotor, includes thesteps of: (a) applying the first-end positioning assembly to connect thefirst-end rotor core and the plurality of connectors to connect thefirst-end positioning assembly; (b) applying the rotation shaft topenetrate through the first-end rotor core in the assembly direction;(c) applying the second-end positioning assembly to connect thesecond-end rotor core; (d) applying the second-end positioning assemblyto connect the plurality of connectors; (e) applying the rotation shaftto penetrate through the second-end rotor core in the assemblydirection; and, (f) disassembling the first-end positioning assemblyfrom the first-end rotor core and the second-end positioning assemblyfrom the second-end rotor core, and then the rotation shaft beingassembled with the first-end rotor core and the second-end rotor core.

In one embodiment of the present invention, between the step (b) and thestep (c), the method for assembling a permanent magnet motor rotorfurther includes the steps of: (b1) applying a middle positioningassembly to connect a middle rotor core; (b2) applying the middlepositioning assembly to connect the plurality of connectors so as tohave the rotation shaft to penetrate through the middle rotor core inthe assembly direction and a front shaft end of the rotation shaft toexpose out of the middle rotor core; and, (b3) disassembling the middlepositioning assembly from the middle rotor core.

As stated above, the apparatus for assembling a permanent magnet motorrotor and the method thereof provided by this invention apply thefirst-end positioning assembly, the connectors and the second-endpositioning assembly to mount the first-end rotor core and thesecond-end rotor core onto the rotation shaft without utilizing the keyplates and the key ways. Thereupon, the manufacturing cost anddifficulty can be reduced, and also the maintainability can be enhanced.

All these objects are achieved by the apparatus for assembling apermanent magnet motor rotor and the method thereof described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be specified with reference to itspreferred embodiment illustrated in the drawings, in which:

FIG. 1 is a schematic view of a rotation shaft and a key plate in theart;

FIG. 2 demonstrates schematically the rotation shaft of FIG. 1 mountedwith a first rotor core in the art;

FIG. 3 demonstrates schematically the rotation shaft of FIG. 1 mountedwith a sectional skewed rotor assembly in the art;

FIG. 4 is a schematic exploded view of a first embodiment of theapparatus for assembling a permanent magnet motor rotor in accordancewith the present invention;

FIG. 5 demonstrates schematically perspective views of the rotationshaft and the rotor core in accordance with the present invention;

FIG. 6 demonstrates schematically an assembly process applying the firstembodiment of the apparatus for assembling a permanent magnet motorrotor in accordance with the present invention;

FIG. 7 is a schematic view of a sectional skewed rotor assemblyassembled by the process of FIG. 6 in accordance with the presentinvention;

FIG. 8 is a schematic exploded view of a second embodiment of theapparatus for assembling a permanent magnet motor rotor in accordancewith the present invention;

FIG. 9 to FIG. 11 demonstrate schematically an assembly process applyingthe second embodiment of the apparatus for assembling a permanent magnetmotor rotor in accordance with the present invention; and

FIG. 12 is a schematic view of a sectional skewed rotor assemblyassembled by the second embodiment of the apparatus for assembling apermanent magnet motor rotor in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention disclosed herein is directed to an apparatus forassembling a permanent magnet motor rotor and a method thereof. In thefollowing description, numerous details are set forth in order toprovide a thorough understanding of the present invention. It will beappreciated by one skilled in the art that variations of these specificdetails are possible while still achieving the results of the presentinvention. In other instance, well-known components are not described indetail in order not to unnecessarily obscure the present invention.

Refer to FIG. 4 through FIG. 5; where FIG. 4 is a schematic explodedview of a first embodiment of the apparatus for assembling a permanentmagnet motor rotor in accordance with the present invention, and FIG. 5demonstrates schematically perspective views of the rotation shaft andthe rotor core in accordance with the present invention. As shown, theapparatus for assembling a permanent magnet motor rotor 1 includes afirst-end positioning assembly 11, a plurality of connectors 12 (twoshown in the figure, but with only one labeled) and a second-endpositioning assembly 13.

The apparatus for assembling a permanent magnet motor rotor 1 is usedfor a rotation shaft 21 to penetrate therethrough along an assemblydirection D (see FIG. 6) and thus to be assembled to a first-end rotorcore 22 (see FIG. 6) and a second-end rotor core 23. The rotation shaft21 has a front shaft end 211. The second-end rotor core 23 is furnishedwith a second-core through hole 231 for receiving the rotation shaft 21,a plurality of second-rotor through holes 232 (only one labeled in thefigure) and a plurality of second rotor grooves 233 (only one labeled inthe figure), in which the second rotor grooves 233 are disposed at aperipheral surface of the second-end rotor core 23. The first-end rotorcore 22, structurally resembled to the second-end rotor core 23, is alsofurnished with a first-core through hole, a plurality of first-rotorthrough holes and a plurality of first rotor grooves disposed at aperipheral surface of the first-end rotor core 22.

The first-end positioning assembly 11, provided with at least one firstpositioning element, is furnished with a first through hole 112 for therotation shaft 21 to penetrate therethrough, and a plurality of firstpositioning holes 113 corresponding to the connectors 12. In thisembodiment, the first-end positioning assembly 11 has two firstpositioning elements 111 shaped to be cylindrical structures. The twofirst positioning elements 111 are used for engaging the two first-rotorthrough holes of the first-end rotor core 22, so as to fix the first-endrotor core 22, and to prevent the first-end rotor core 22 fromdisplacing or rotating with respect to the first-end positioningassembly 11. A quantity of the first positioning elements 111 can be,but not limited to, one, and can be shaped to be non-circular. Inaddition, the first positioning elements 111 can be plugged into thecorresponding first-rotor through holes, and thereby the first-end rotorcore 22 can be fixed.

The second-end positioning assembly 13 is largely resembled to thefirst-end positioning assembly 11, but provided with a difference atpositions of the second positioning elements 131. The second throughhole 132 is positioned in correspondence to the first through hole 112,and the second positioning holes 133 are positioned in correspondence tothe respective first positioning holes 113.

Two first longitudinal axes X1 for the two first positioning elements111 to extend individually in the assembly direction D are separatedfrom two corresponding second longitudinal axes X2 for the two secondpositioning element 131 to extend individually in the assembly directionD. Since the first positioning element 111 and the second positioningelement 131 are plugged into the first-rotor through hole and thesecond-rotor through hole 232, respectively, and thus the first-rotorthrough hole and the second-rotor through hole 232 would be driven togenerate offsets.

In this embodiment, the two first positioning elements 111 aresymmetrical to the first through hole 112, and the two secondpositioning elements 131 are symmetrical to the second through hole 132.Thus, the two first positioning elements 111 can be connected to form afirst reference line L1, and the two second positioning elements 131 areconnected to form a second reference line L2. When the first referenceline L1 and the second reference line L2 are projected in the assemblydirection D onto the same plane (i.e., the second-end rotor core 23), anangle would be formed between the first reference line L1 and the secondreference line L2. In particular, the angle is ranging from 1° to 45°,and it implies that the first reference line L1 and the second referenceline L2 will not coincide.

Then, refer to FIG. 4 through FIG. 7; where FIG. 6 demonstratesschematically an assembly process applying the first embodiment of theapparatus for assembling a permanent magnet motor rotor in accordancewith the present invention, and FIG. 7 is a schematic view of asectional skewed rotor assembly assembled by the process of FIG. 6 inaccordance with the present invention. As shown, the first-endpositioning assembly 11 is positioned onto the first-end rotor core 22,and the second-end positioning assembly 13 is positioned onto thesecond-end rotor core 23, while the connectors 12 connect the first-endpositioning assembly 11 and the second-end positioning assembly 13 so asto ensure that no relative rotation would be generated between thefirst-end positioning assembly 11 and the second-end positioningassembly 13.

In this embodiment, the first-end positioning assembly 11 and thesecond-end positioning assembly 13 are furnished with the firstpositioning holes 113 and the second positioning holes 133,respectively, for the respective connectors 12 to penetrate therethroughin a tight fit. However, in some other embodiments, at least one lockingelement can be applied to fix the first-end positioning assembly 11 andthe second-end positioning assembly 13, respectively, with theconnectors 12. As such, the locking element can be a screw, a nut or aquick-release structure.

The rotation shaft 21 is to penetrate orderly the first through hole112, the first-end rotor core 22, the second-end rotor core 23 and thesecond through hole 132 in the assembly direction D, and then to havethe first-end rotor core 22 and the second-end rotor core 23 to beassembled together. Since the rotation shaft 21 here does not includethe aforesaid key plates PA12 and key ways PA111, thus the tight fitbetween the rotation shaft 21 and the first-end rotor core 22 or thesecond-end rotor core 23 can be obtained through structuralinterference, gluing, knurling or other tight-fit means.

After the rotation shaft 21 is assembled to the first-end rotor core 22and the second-end rotor core 23, a sectional skewed rotor assembly 2 isformed. As shown, the first-end rotor core 22 and the second-end rotorcore 23 demonstrate different sections of this rotor assembly 2, and thefirst rotor grooves 223 and the second rotor grooves 233 are arranged inan offset manner.

Finally, refer to FIG. 5, FIG. 8 through FIG. 12; where FIG. 8 is aschematic exploded view of a second embodiment of the apparatus forassembling a permanent magnet motor rotor in accordance with the presentinvention, FIG. 9 to FIG. 11 demonstrate schematically an assemblyprocess applying the second embodiment of the apparatus for assembling apermanent magnet motor rotor in accordance with the present invention,and FIG. 12 is a schematic view of a sectional skewed rotor assemblyassembled by the second embodiment of the apparatus for assembling apermanent magnet motor rotor in accordance with the present invention.As shown, the apparatus for assembling a permanent magnet motor rotor 1a includes a first-end positioning assembly 11, a plurality ofconnectors 12 (two shown in the figure, but with only one labeled), asecond-end positioning assembly 13 a and at least one middle positioningassembly 14 a (one shown in the figure).

The difference between this apparatus for assembling a permanent magnetmotor rotor 1 a and the previous first embodiment of the apparatus forassembling a permanent magnet motor rotor 1 is at the second-endpositioning assembly 13 a and the middle positioning assembly 14 a ofthis embodiment 1a, and all other elements are largely the same. Thus,details for these identical elements of the two embodiments 1, 1a wouldbe omitted herein.

The second-end positioning assembly 13 a and the first-end positioningassembly 11 are structurally similar, and the only difference in betweenis the position of the second positioning element 131 a. The secondthrough hole 132 a is disposed in correspondence to the first throughhole 112, and the second positioning hole 133 a is disposed incorrespondence to the first positioning hole 113. Similarly, the middlethrough hole 142 a of the middle positioning assembly 14 a is disposedin correspondence to the first through hole 112, and the middlepositioning hole 143 a is disposed in correspondence to the firstpositioning hole 113. The middle positioning assembly 14 a is used forfixing a middle rotor core 24 a, which is structurally resembled to thefirst-end rotor core 22.

Two first longitudinal axes X1 for the two first positioning elements111 to extend individually in the assembly direction D, two secondlongitudinal axes X2 a for the two second positioning elements 131 a toextend individually in the assembly direction D, and two thirdlongitudinal axes X3 a for the two middle positioning elements 141 a toextend individually in the assembly direction D are all separated toeach other by offsetting.

A connection line of the two second positioning elements 131 a isdefined as a second reference line L2 a, and that of the two middlepositioning elements 141 a is defined as a third reference line L3 a. Inthis embodiment, similar to the first embodiment, when the firstreference line L1, the second reference line L2 a and the thirdreference line L3 a are projected onto the same plane, angles would beformed for every two reference lines. It implies that the firstreference line L1, the second reference line L2 a and the thirdreference line L3 a do not coincide to each other (as the three dashedlines shown in FIG. 5).

The first-end positioning assembly 11 fixes the first-end rotor core 22,and the middle positioning assembly 14 a fixes the middle rotor core 24a, while the connectors 12 connect the first-end positioning assembly 11and the middle positioning assembly 14 a so as to ensure that norelative rotation would be generated between the first-end positioningassembly 11 and the middle positioning assembly 14 a. The rotation shaft21 is operated to penetrate through the first through hole 112, thefirst-end rotor core 22, the middle rotor core 24 a and the middlethrough hole 142 a orderly in the assembly direction D. It shall beexplained that, in this embodiment including more than two rotor cores,only a front shaft end 211 of the rotation shaft 21 is exposed in theassembly direction D.

Then, the middle positioning assembly 14 a is disassembled from themiddle rotor core 24 a and the connectors 12. Further, after thesecond-end positioning assembly 13 a is fixed onto the second-end rotorcore 23 a by engaging the connectors 12, the second-end rotor core 23 acan contact the middle rotor core 24 a.

The rotation shaft 21 is operated to penetrate through the second-endrotor core 23 a and the second through hole 132 a orderly in theassembly direction D. After the rotation shaft 21 is assembled bypenetrating to the first-end rotor core 22, the middle rotor core 24 aand the second-end rotor core 23 a, the first-end positioning assembly11 and the second-end positioning assembly 13 a are disassembled fromthe first-end rotor core 22 and the second-end rotor core 23 a,respectively. As such, a sectional skewed rotor assembly 2 a is formed.As shown in FIG. 12, this sectional skewed rotor assembly 2 a has threesections; the first-end rotor core 22, the middle rotor core 24 a andthe second-end rotor core 23 a. In addition, the first rotor grooves223, the middle rotor grooves 243 a and the second rotor grooves 233 aare arranged in an offset manner to each other.

In this embodiment, one middle positioning assembly 14 a is taken as atypical example. However, it shall be understood that plural middlepositioning assemblies 14 a can be also applied in accordance with theaforesaid method. In other words, this invention is not limited to theassembly having only two or three sections of rotor cores, but theassembly having more than three rotor cores can be still applied. Theonly requirement is that at least two of the third longitudinal axes X3a extending the corresponding middle positioning elements 141 a of themiddle positioning assembly 14 a in the assembly direction D are offsetarranged to each other. Preferably, all the first longitudinal axes X1,the second longitudinal axes X2 a and the third longitudinal axes X3 aare offset to each other. In addition, to assemble multiple rotor cores,the rotor cores that are penetrated through by the rotation shaft 21shall be fixed by the corresponding middle positioning assemblies 14 a,and thus the front shaft end 211 can be exposed. Then, by disassemblingthe middle positioning assemblies 14 a till the rotor core penetratingthe rotation shaft 21 is fixed by the second-end rotor core 23 a, thefinal sectional skewed rotor assembly can be obtained.

It shall be explained that the basis for naming in this invention isbased on the end. Referring to FIG. 4 and FIG. 8, the second-endpositioning assembly 13 and the middle positioning assembly 14 a areactually the same structurally. In FIG. 8, three positioning assembliesare included. Among the three positioning assemblies, the middlepositioning assembly 14 a is adjacent to neither the first end nor thesecond end. Though the middle positioning assembly 14 a is structurallythe same as the second-end positioning assembly 13, yet, in the secondembodiment, it can only be named as the middle positioning assembly 14a, not the second-end positioning assembly 13 a. Thus, no matter howmany middle positioning assemblies 14 a are, the positioning assemblydisposed at the first end or the second end, it will be always named asthe first-end positioning assembly or the second-end positioningassembly, respectively. Each of the other positioning assemblies locatedbetween the first-end positioning assembly and the second-endpositioning assembly would be named as the middle positioning assembly.

In all embodiments provided in this disclosure, even though all thepositioning elements (the first positioning element, the secondpositioning element, the middle positioning element) are offsetarranged, yet the rotor cores (the first-end rotor core, the second-endrotor core, the middle rotor core) can be structurally the same.

It shall be explained that, in the embodiments of the present invention,the rotor cores are sketched according to, but not limited to, a typicalsurface permanent magnet (SPM) motor. In particular, this invention canbe also applied to assemble the rotor cores of an interior permanentmagnet (IPM) motor.

In addition, a method for assembling a permanent magnet motor rotor inaccordance with the present invention is performed by utilizing theaforesaid first or second embodiment of the apparatus for assembling apermanent magnet motor rotor. This method includes the following StepS101 to Step S106.

Step S101: Apply the first-end positioning assembly to connect thefirst-end rotor core, and apply the plurality of connectors to connectthe first-end positioning assembly and the first-end rotor core.

Step S102: Apply the rotation shaft to penetrate through the first-endrotor core in the assembly direction.

Step S103: Apply the second-end positioning assembly to connect thesecond-end rotor core.

Step S104: Apply the plurality of connectors to connect the second-endpositioning assembly and the second-end rotor core.

Step S105: Apply the rotation shaft to penetrate through the second-endrotor core in the assembly direction.

Step S106: Disassemble the first-end positioning assembly from thefirst-end rotor core and the second-end positioning assembly from thesecond-end rotor core, such that the rotation shaft can be assembledwith the first-end rotor core and the second-end rotor core.

Referring to FIG. 6 and FIG. 7, in the aforesaid Step S101 to S106,orders of the two operations in Step S101 can be switched, and alsoorders of the two disassembling steps in Step S106 (the first-endpositioning assembly from the first-end rotor core, and the second-endpositioning assembly from the second-end rotor core) can be switched. Iftwo rotor cores are included, Step S102 and Step S105 can be integratedinto a step to be performed after Step S104.

Between Step S102 and Step S103, Step S201 to Step S203 can be included.

Step S201: Apply a middle positioning assembly to connect a middle rotorcore.

Step S202: Apply the plurality of connectors to connect the middlepositioning assembly and the middle rotor core, such that the rotationshaft can penetrate through the first-end rotor core and the middlerotor core simultaneously in the assembly direction by having a frontshaft end of the rotation shaft to expose out of the middle rotor core.

Step S203: Disassemble the middle positioning assembly from the middlerotor core.

The aforesaid Step S201 to S203 can be referred to FIG. 9 and FIG. 10.

In summary, the apparatus for assembling a permanent magnet motor rotorand the method thereof provided by this invention is to apply thefirst-end positioning assembly, the connectors and the second-endpositioning assembly to mount the first-end rotor core and thesecond-end rotor core onto the rotation shaft. In comparison with thekey plates and the key ways in the art, the apparatus for assembling apermanent magnet motor rotor and the method thereof of this inventioncan reduce the manufacturing cost and difficulty. According to thisinvention, the rotor core is detachable, and thus the maintainabilitycan be enhanced. In addition, since the rotor core of this invention isfurnished with no buckling slot for receiving the key plate, thusunbalance upon the rotor core can be reduced.

While the present invention has been particularly shown and describedwith reference to a preferred embodiment, it will be understood by thoseskilled in the art that various changes in form and detail may bewithout departing from the spirit and scope of the present invention.

What is claimed is:
 1. A method for assembling a permanent magnet motorrotor, performed by utilizing an apparatus for assembling a permanentmagnet motor rotor, the apparatus used for a rotation shaft to penetratethrough and thus be assembled with a first-end rotor core and asecond-end rotor core in an assembly direction, the apparatus comprisinga first-end positioning assembly, a plurality of connectors, and asecond-end positioning assembly, the first-end positioning assemblybeing furnished with a first through hole, the second-end positioningassembly being furnished with a second through hole, the first-end rotorcore being furnished with a plurality of first-rotor through holes, thesecond-end rotor core being furnished with a plurality of second-rotorthrough holes, and the method comprising the steps of: (a) applying thefirst-end positioning assembly to connect the first-end rotor core andthe connectors to connect the first-end positioning assembly by pluggingat least one first positioning element of the first-end positioningassembly into at least one of the first-rotor through holes of thefirst-end rotor core so as to fix the first-end rotor core; (b) applyingthe rotation shaft to penetrate through the first through hole of thefirst-end positioning assembly, and the first-end rotor core in theassembly direction; (c) applying the second-end positioning assembly toconnect the second-end rotor core by plugging at least one secondpositioning element of the second-end positioning assembly into at leastone of the second-rotor through holes of the second-end rotor core so asto fix the second-end rotor core; (d) applying the second-endpositioning assembly to connect the connectors; (e) applying therotation shaft to penetrate through the second-end rotor core, and thesecond through hole of the second-end positioning assembly in theassembly direction; and (f) disassembling the at least one firstpositioning element of the first-end positioning assembly from thefirst-end rotor core and the at least one second positioning element ofthe second-end positioning assembly from the second-end rotor core, andthen the rotation shaft being assembled with the first-end rotor coreand the second-end rotor core; wherein a first longitudinal axis foreach of the at least one first positioning element to extendindividually in the assembly direction and a second longitudinal axisfor each of the at least one second positioning element to extendindividually in the assembly direction are arranged in an offset manner.2. The method for assembling a permanent magnet motor rotor of claim 1,between the step (b) and the step (c), further including the steps of:(b1) applying a middle positioning assembly to connect a middle rotorcore; (b2) applying the middle positioning assembly to connect theplurality of connectors so as to have the rotation shaft to penetratethrough the middle rotor core in the assembly direction and a frontshaft end of the rotation shaft to expose out of the middle rotor core;and (b3) disassembling the middle positioning assembly from the middlerotor core.